oflate when I go to a webpage without connecting to the net,I'm being redirected to some page(see pic)

The link for Try Again is : chrome://global/content/netError.xhtml?e=dnsNotFound&u=http%3A//www.thinkdigit.com/forum/&d=www.thinkdigit.com%20could%20not%20be%20found.%20Please%20check%20the%20name%20and%20try%20again.#

I suspect it to be a spyware.I ran MS Anti-Spy,Spy Bot S&D and Webroot Spysweeper,but the page still appears.

I think you have set your homepage to thinkdigit forum site and if you are starting the browser without connecting to the net, you will get a address not found error... Try to start the browser with no pages or a blank page...